JP2021089180A - Target detection device and target detection method - Google Patents

Abstract

To provide a target detection device and a target detection method, allowing for detection of a target by simple constitution.SOLUTION: A target detector 1 comprises: a transmit array 11 having a plurality of transmit elements 11a; and a signal generation unit 111 generating a plurality of sets of electric signals including a first set of electric signals and a second set of electric signals differing from the first set, in such a way that phases are different for each set. The plurality of transmit elements 11a are grouped in accordance with a plurality of group constitutions including a first and a second group constitution. In the first group constitution, the transmit elements 11a are grouped into a plurality of groups, each of which includes n transmit elements 11a, and in the second group constitution, the transmit elements 11a are grouped into a plurality of groups, each of which includes m transmit elements 11a, the m being different from the n. The first and second sets of electric signals are input to each group of the first and second group constitutions, respectively.SELECTED DRAWING: Figure 11

Description

The present invention relates to a target detection device and a target detection method that transmit a transmitted wave and detect a target based on the reflected wave.

Conventionally, a target detection device that transmits a transmitted wave and detects a target based on the reflected wave is known. In this type of target detection device, in order to detect the position of the target in the angle range of the detection target, it is necessary to specify the arrival direction of the reflected wave in the angle range. As a method for this, for example, a wave transmitting array in which a plurality of transmitting elements are arranged at a pitch of half or more the wavelength of the transmitted wave can be used. By adjusting the pitch of the wave transmitting element in this way, a grating lobe is generated. The grating lobe is generated in a direction tilted by a predetermined angle with respect to the front direction of the wave transmission array. By adjusting the pitch of the wave transmitting element, the wave transmitting direction of the grating lobe can be adjusted. Therefore, when the grating lobe is used as the transmission wave, the transmission direction of the transmission wave can be specified by the pitch of the transmission element, and as a result, the arrival direction of the reflected wave can be specified.

As a method of covering the angular range of the detection target with a grating lobe, a method of arranging a plurality of transmission arrays having the above configuration by changing their orientations in the angular direction can be used. In this configuration, for example, each transmission array produces two transmission beams with different transmission directions. Each transmission array is arranged so that the transmission beam transmitted from another transmission array fills the gap between the two transmission beams transmitted from one transmission array. As a result, each transmission array is associated with the transmission direction within the angle range of the detection target. Therefore, the receiving direction of the reflected wave can be specified depending on which transmission array is used to transmit the wave.

Patent Document 1 discloses this type of target detection device.

U.S. Patent Application Publication No. 2018/0100922

Since the target detection device having the above configuration uses a plurality of wave transmission arrays, the configuration of the target detection device becomes complicated and the cost increases.

In view of such a problem, an object of the present invention is to provide a target detection device and a target detection method capable of detecting a target with a simple configuration.

The first aspect of the present invention relates to a target detection device. The target detection device according to this aspect includes a transmission array having a plurality of transmission elements for converting an electric signal into a transmission wave, a first set of electric signals, and a second set of electric signals different from the first set. It is provided with a signal generation unit that generates a plurality of sets of electric signals including the set of the above with different phase settings for each set. The target detection device groups the plurality of wave-transmitting elements according to a plurality of group configurations including a first group configuration and a second group configuration, and in the first group configuration, n of the wave-transmitting elements. The plurality of transmitting elements are grouped into a plurality of groups each having, and in the second group configuration, the plurality of transmitting elements are grouped into a plurality of groups each having m different transmitting elements different from the n elements. Group the elements. Then, the electric signals of the first set are input to each group of the first group configuration, and the electric signals of the second set are input to each group of the second group configuration.

According to the target detection device according to the first aspect, the grating lobe transmitted from the wave transmitting elements grouped according to the first group configuration and the wave transmitted from the transmitting elements grouped according to the second group configuration. The direction of wave transmission can be different from that of the grating lobe. Therefore, one transmission array can transmit a plurality of transmission beams (grating lobes) having different transmission directions. Therefore, the target can be detected smoothly with a simple configuration.

In the target detection device according to the first aspect, the signal generation unit generates the first set of electric signals having the same phase shift between the electric signals, and the first set of electric signals having the same phase shift between the electric signals. It may be configured to generate two sets of electrical signals.

Further, the plurality of transmitting elements used in the first group configuration and the plurality of transmitting elements used in the second group configuration may be the same.

According to this configuration, since a common transmitting element is used for the first group configuration and the second group configuration, it is not necessary to prepare a transmitting element for each of the first group configuration and the second group configuration. .. Therefore, the configuration of the wave transmission array can be simplified and the cost can be reduced.

Further, it is preferable that the plurality of wave transmitting elements are arranged at equal intervals.

In this way, by making the spacing between the wave transmitting elements constant, for example, by adjusting the phases of the electric signals of the first set and the second set, the grating lobe appears smoothly in the predetermined wave transmitting direction. Can be made to.

In the target detection device according to the first aspect, the n can be a multiple of the number of the electric signals of the first set.

Further, the m can be a multiple of the number of the electric signals of the second set.

The target detection device according to the first aspect is a superimposition circuit that superimposes the first set of electric signals and the second set of electric signals and inputs the superposed electric signals to the plurality of transmitting elements. Can be further prepared.

According to this configuration, the grating lobe based on the first set of electric signals and the grating lobe based on the second set of electric signals can be simultaneously transmitted. Therefore, it is possible to quickly detect a target in the detection area.

Alternatively, in the target detection device according to the first aspect, the first set of electric signals and the second set of electric signals are input, and first, the first set of electric signals is transmitted. A switching circuit that outputs to the array and then outputs the second set of electrical signals to the wave transmission array may be further provided.

According to this configuration, the grating lobe based on the first set of electric signals and the grating lobe based on the second set of electric signals can be transmitted in a time-division manner.

In the target detection device according to the first aspect, it is preferable that the frequencies of the first set of electric signals and the frequencies of the second set of electric signals are different.

According to this configuration, the received signal based on the grating lobe of the first set of electric signals and the received signal based on the grating lobe of the second set of electric signals can be extracted by frequency. Therefore, for example, even when these two grating lobes are transmitted at the same time, the received signal based on each grating lobe can be appropriately extracted, and the target existing in the direction of each grating globe can be smoothly detected.

In the target detection device according to the first aspect, the signal generation unit may be configured to change the frequencies of the first set of electrical signals and the second set of electrical signals.

According to this configuration, by changing the frequency, the transmission direction of the grating lobe based on the first set of electric signals and the second set of electric signals can be changed. Thereby, each of these grating lobes can scan a predetermined angle range, and the detection range of the target can be expanded.

The target detection device according to the first aspect includes a receiving array including at least one receiving element that receives the reflected wave generated by the reflection of the transmitted wave on the target and converts the reflected wave into a received signal. Further prepared.

In this case, the target detection device further includes a received signal processing unit that processes the received signal, and the received signal processing unit is based on the reflected wave corresponding to the frequency based on the frequency component of the received signal. It may be configured to extract isofrequency received signals.

According to this configuration, by extracting a signal having the same frequency as the frequency of the electric signal used for transmission from the reception signal, it is possible to acquire a reception signal based on each grating lobe transmitted from the transmission array. Therefore, the target can be properly detected based on the received signal.

In this case, the received signal processing unit may be configured to acquire the isofrequency received signal corresponding to each frequency by extracting a plurality of frequency components extracted at different frequencies from the received signal.

Alternatively, the received signal processing unit may be configured to calculate the frequency spectrum of the received signal and acquire the isofrequency received signal corresponding to each frequency based on the frequency spectrum.

In the target detection device according to the first aspect, the receiving array includes a plurality of receiving elements, and the received signal processing unit executes beamforming based on the received signal generated from each receiving element. , The beamforming may be configured to calculate the direction of arrival of the reflected wave from the target.

In the target detection device according to the first aspect, the receiving array includes a plurality of receiving elements, and the receiving array is different from the transmitting array and is based on a received signal generated from each receiving element. The received beam generated by the above wave can be configured to intersect the transmitted beam generated by the wave transmitting array.

According to this configuration, the distribution of intensity data based on the intensity of the reflected wave can be calculated in the range where the received beam and the transmitted beam (grating lobe) intersect. Therefore, by changing the directivity direction of the received beam within the detection range by beamforming, it is possible to construct the intensity data of the reflected wave distributed three-dimensionally in the detection range.

The target detection device according to the first aspect is, for example, a sonar that detects a target in water.

Alternatively, the target detection device according to the first aspect may be a radar that detects a target in the air.

A second aspect of the present invention relates to a target detection method. In the target detection method according to this aspect, the transmission array is subjected to a plurality of group configurations in which the plurality of transmitting elements include a first group configuration and a second group configuration for transmitting the transmitted wave. Grouped. Here, in the first group configuration, the plurality of transmitting elements are grouped into a plurality of groups each having n said transmitting elements, and in the second group configuration, the number is different from the n elements. The plurality of transmitter elements are grouped into a plurality of groups each having m of the transmitter elements. Then, in the target detection method, a plurality of sets of electric signals including a first set of electric signals and a second set of electric signals different from the first set are set in different phases for each set. The electric signals of the first set are input to each group of the first group configuration, and the electric signals of the second set are input to each group of the second group configuration. ..

According to the target detection method according to the second aspect, as in the first aspect, a plurality of transmission beams (grating lobes) having different transmission directions can be transmitted by one transmission array. Therefore, the target can be detected smoothly with a simple configuration.

As described above, according to the present invention, it is possible to provide a target detection device and a target detection method capable of detecting a target with a simple configuration.

The effects or significance of the present invention will be further clarified by the description of the embodiments shown below. However, the embodiments shown below are merely examples when the present invention is put into practice, and the present invention is not limited to those described in the following embodiments.

FIG. 1 is a diagram showing a configuration of a wave transmission system according to a reference example. FIG. 2 is a diagram showing a configuration of a wave transmission system according to an embodiment. FIG. 3A is a diagram showing a configuration of a phase adjustment circuit according to an embodiment. FIG. 3B is a diagram showing a configuration of a superimposition circuit according to the embodiment. FIG. 4A is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 4B is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 5A is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 5B is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 6A is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 6B is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 6C is a simulation obtained by simulation of the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the embodiment. The result. FIG. 7A is a simulation obtained by simulation of the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the embodiment. The result. FIG. 7B is a simulation obtained by simulation of the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the embodiment. The result. FIG. 8A is a simulation obtained by simulation of the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the embodiment. The result. FIG. 8B is a simulation obtained by simulation of the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the embodiment. The result. FIG. 9 is a diagram schematically showing a wave transmission mode of the two transmission beams according to the embodiment. FIG. 10 is a diagram schematically showing a configuration example of a transmission / reception system according to an embodiment. FIG. 11 is a block diagram showing a specific configuration of the target detection device 1 according to the embodiment. FIG. 12A is a functional block diagram showing a configuration example of the received signal processing unit 123 according to the embodiment. FIG. 12B is a functional block diagram showing another configuration example of the received signal processing unit 123 according to the embodiment. FIG. 13A is a flowchart showing a process of transmitting a transmitted wave from a wave transmitting element grouped according to the first group configuration according to the embodiment. FIG. 13B is a flowchart showing a process of transmitting a transmitted wave from a wave transmitting element grouped according to the second group configuration according to the embodiment. FIG. 14 is a flowchart showing a process of processing a received signal and displaying a detected image according to the embodiment. FIG. 15 is a diagram schematically showing a configuration when the target detection device according to the embodiment is used as a sonar for detecting a target in water. FIG. 16 is a diagram showing a configuration of a wave transmission system according to the first modification. FIG. 17 is a diagram showing a configuration of a wave transmission system according to the second modification. FIG. 18A shows the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the second modification by simulation. This is a simulation result. FIG. 18B shows the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the second modification by simulation. This is a simulation result. FIG. 19A shows the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the second modification by simulation. This is a simulation result. FIG. 19B shows the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the second modification by simulation. This is a simulation result. FIG. 19C shows the appearance form of the grating lobe when the first set of electric signals is applied to the transmitting elements of each group according to the first group configuration according to the second modification by simulation. This is a simulation result. FIG. 20A shows the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the second modification by simulation. This is a simulation result. FIG. 20B shows the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the second modification by simulation. This is a simulation result. FIG. 21A shows the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the second modification by simulation. This is a simulation result. FIG. 21B shows the appearance form of the grating lobe when the second set of electric signals is applied to the transmitting elements of each group according to the second group configuration according to the second modification by simulation. This is a simulation result.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Basic configuration>
First, the basic configuration of the transmission / reception system of the target detection device according to the present embodiment will be described.

FIG. 1 is a diagram showing a configuration of a wave transmission system according to a reference example.

In the configuration of FIG. 1, a wave transmission array 10 in which a plurality of wave transmission elements 10a are arranged side by side in a row is used. Here, for convenience, 14 transmitting elements 10a are shown, but the number of transmitting elements 10a is not limited to this. In FIG. 1, for convenience, each wave transmitting element 10a is numbered in order from the top.

In this configuration example, a sine wave electric signal is supplied from the transmission circuits 20a and 20b with four continuously arranged wave transmission elements 10a as one set. Therefore, the four transmitting elements 10a included in one set function as one transmitting region. The pitch between the sets is set to half or more of the wavelength of the electric signal output from the transmission circuits 20a and 20b. Therefore, the pitch of the wave transmission region is set to half or more of the wavelength of the electric signal. In this way, by setting the pitch of the transmission region (the pitch of each set) to half or more of the wavelength of the electric signal, the grating lobe can be transmitted from the transmission array 10.

The transmission circuits 20a and 20b each output a sine wave electric signal. The transmission circuits 20a and 20b output electric signals at the same frequencies as each other. The phase of the electric signal output from the transmission circuit 20b is 90 ° ahead of the electric signal output from the transmission circuit 20a.

Of the four transmission elements 10a included in one set, the first and third transmission elements 10a are supplied with electric signals from the transmission circuit 20a, and the second and fourth transmission elements 10a are supplied with electric signals. , An electric signal is supplied from the transmission circuit 20b. Electric signals are supplied to the third and fourth transmission elements 10a from the transmission circuits 20a and 20b, respectively, in a phase-inverted state. The phase inversion is performed, for example, by inverting the polarity of the connection of the signal lines from the transmission circuits 20a and 20b to the wave transmitting element 10a. In addition, a phase adjustment circuit for inverting the phase may be arranged.

By supplying the electric signal to each of the transmitting elements 10a in this way, the electric signal is supplied to the four transmitting elements 10a of each set in a state where the phases are shifted by 90 ° from each other. As a result, the transmitted wave can be output from the wave transmitting array 10 in a state where only one grating lobe appears on only one side while extinguishing the main lobe. Then, by changing the frequency of the electric signal output from the transmission circuits 20a and 20b, the direction of the grating globe can be changed in the arrangement direction of the wave transmitting elements 10a. As a result, the angle between the front direction of the wave transmission array 10 and the direction of the transmitted wave can be changed, and the transmitted wave can be scanned in the angle direction.

In this way, the transmission direction of the transmitted wave and the frequency of the electric signal are associated with each other. Therefore, the transmission direction of the transmitted wave can be specified by the frequency of the received signal generated by receiving the reflected wave of the transmitted wave by the receiver. That is, the direction of the target that generated the reflected wave can be specified by the frequency of the received signal.

In the above, the phase shift between the transmitting elements 10a is set to 90 °, but the phase shift is not limited to this. For example, even if the phase shift between the wave transmitting elements 10a is set to 60 ° or 45 °, only one grating lobe can appear on only one side while extinguishing the main lobe. For example, when the phase shift is set to 60 °, the six transmitter elements 10a are set to one set, and the six transmitter elements 10a of each set are set to 0 °, 60 °, 120 °, 180 °, An electric signal having a phase of 240 ° and 300 ° is supplied. When the phase shift is set to 45 °, the eight transmitting elements 10a are set to one set, and the eight transmitting elements 10a of each set are set to 0 °, 45 °, 90 °, 135 °, and so on. An electric signal having a phase of 180 °, 225 °, 270 °, and 315 ° is supplied. Also in these cases, by changing the frequency of the electric signal, the direction of the grating globe can be changed in the arrangement direction of the wave transmitting elements 10a, and thereby the transmitting direction of the transmitted wave can be changed.

In the configuration of FIG. 1, since only one grating lobe is scanned, the scanning range of the transmitted wave is narrow. Therefore, in the present embodiment, by supplying a plurality of sets of electric signals having different phase shifts to the plurality of transmitting elements 10a, a plurality of grating lobes having different directions are generated. Then, by changing the frequency of each set of electric signals, the wave transmission direction is changed for each grating lobe, and the grating lobe is scanned. This expands the entire scanning range.

FIG. 2 is a diagram showing a configuration of a wave transmission system according to an embodiment. The description of the plurality of angles in FIG. 2 indicates the phase of the electric signal supplied by each signal line when the phase of the electric signal (sine wave) output from the transmission circuit 21a is 0 °. There is.

In the configuration example of FIG. 2, a wave transmission array 11 in which 72 wave transmission elements 11a are arranged in a row at equal intervals is used. The number of wave transmitting elements 11a is not limited to 72. In FIG. 2, for convenience, each wave transmitting element 11a is numbered in order from the top.

The 72 wave transmitting elements 11a are grouped according to the first group configuration and the second group configuration. In the first group configuration, 72 wave transmitting elements 11a are grouped into a plurality of group GR1s each having four transmitting elements 11a. Further, in the second group configuration, 72 wave transmitting elements 11a are grouped in a plurality of group GR2 each having 6 transmitting elements 11a. Therefore, the 72 transmitting elements 11a used in the first group configuration and the 72 transmitting elements 11a used in the second group configuration are the same as each other. That is, the common wave transmitting element 11a is used for the first group configuration and the second group configuration.

Then, the first set of electrical signals phase-shifted by 90 ° is input to each group GR1 of the first group configuration, and the phase-shifted first set GR2 of the second group configuration is 60 °. Two sets of electrical signals are input. That is, the plurality of electric signals included in the first set have the same phase shift between the electric signals (phase shift 90 °), and the plurality of electric signals included in the second set have the phases between the electric signals. The shifts are equal (phase shift 60 °).

The electric signal output from the transmission circuits 21a and 21b is supplied to the wave transmission element 11a of the group GR1. The pitch of the group GR1 is set to half or more of the wavelength of the electric signal output from the transmission circuits 21a and 21b. Similar to the transmission circuits 20a and 20b of FIG. 1, the transmission circuits 21a and 21b output sinusoidal electric signals whose phases are 90 ° out of phase with each other. The electric signals output from the transmission circuits 21a and 21b are converted into two electric signals by the phase adjustment circuit 23. Of these two systems, the electric signal of the first system marked with + in FIG. 2 is an electric signal having the same phase as the electric signal output from the transmission circuits 21a and 21b, and is marked with-. The electric signal of the second system is an electric signal whose phase is inverted with respect to the electric signal output from the transmission circuits 21a and 21b. The electric signal of each system is input to the corresponding superimposition circuit 24.

The electric signal output from the transmission circuits 22a to 22c is supplied to the wave transmission element 11a of the group GR2. The pitch of the group GR2 is set to half or more of the wavelength of the electric signal output from the transmission circuits 22a to 22c. The transmission circuits 22a to 22c output sinusoidal electric signals whose phases are shifted by 60 ° from each other. The electric signals output from the transmission circuits 22a to 22c are converted into two electric signals by the phase adjusting circuit 23 in the same manner as described above. Of these two systems, the electric signal of the first system marked with + in FIG. 2 is an electric signal having the same phase as the electric signal output from the transmission circuits 22a to 22c, and is marked with −. The electric signal of the second system is an electric signal whose phase is inverted with respect to the electric signal output from the transmission circuits 22a to 22c. The electric signal of each system is input to the corresponding superimposition circuit 24.

FIG. 3A is a diagram showing the configuration of the phase adjustment circuit 23.

The phase adjustment circuit 23 is composed of a transformer in which one coil 23a is arranged on the input side and two coils 23b and 23c are arranged on the output side. The winding directions of the two coils 23b and 23c on the output side are reversed from each other. An electric signal output from any of the transmission circuits 21a, 21b, 22a to 22c is input to the coil 23a on the input side. An electric signal having the same phase as the input electric signal is output from one coil 23b on the output side by electromagnetic induction. This electric signal is the electric signal of the first system.

As described above, the winding direction of the other coil 23c on the output side is opposite to that of the one coil 23b. Therefore, from the other coil 23c, an electric signal in which the phase of the electric signal input to the coil 23a is inverted is output. This electric signal is the electric signal of the second system. In this way, the phase adjustment circuit 23 outputs two systems of electric signals whose phases are opposite to each other.

The configuration of the phase adjusting circuit 23 is not limited to the configuration shown in FIG. 3A, with respect to an electric signal having the same phase as the electric signal output from the transmission circuits 21a, 21b, 22a to 22c, and the electric signal. Other configurations may be used as long as it is possible to generate two systems of electric signals whose phases are inverted.

Returning to FIG. 2, the frequencies of the electric signals output from the transmission circuits 21a and 21b are the same as each other. The transmission circuits 21a and 21b switch the frequency of the electric signal according to the first frequency table. For example, frequencies of 95, 100, 105, 110, 120, 130, and 145 kHz are assigned to the first frequency table. The transmission circuits 21a and 21b cyclically switch the frequencies of the electric signals in the order of the frequencies assigned to the first frequency table.

Further, the frequencies of the electric signals output from the transmission circuits 22a to 22c are the same as each other. The transmission circuits 22a to 22c switch the frequency of the electric signal according to the second frequency table. The frequencies assigned to the second frequency table are different from the frequencies assigned to the first frequency table. The second frequency table is assigned frequencies of, for example, 115, 125, 135, 150 kHz. The transmission circuits 22a to 22c cyclically switch the frequencies of the electric signals in the order of the frequencies assigned to the second frequency table.

FIG. 3B is a diagram showing the configuration of the superimposition circuit 24.

The superimposition circuit 24 is composed of a transformer in which two coils 24a and 24b are arranged on the input side and one coil 24c is arranged on the output side. The two coils 24a and 24b on the input side have the same winding direction. The electric signals of the first set and the second set are input to the two coils 24a and 24b from the corresponding phase adjusting circuits 23, respectively. The electric signals input to the coils 24a and 24b on the input side are superimposed by electromagnetic induction and output from the coils 24c on the output side. The output electric signal includes each frequency component of the two input electric signals.

In the configuration of FIG. 2, the phase adjustment circuit 23 inverts the phase of the electric signals output from the transmission circuits 21a, 21b, 22a to 22c, but the current flowing through the coils 24a, 24b is in the opposite direction to the normal time. By connecting the transmission circuits 21a, 21b, 22a to 22c and the coils 24a, 24b so as to be, the phase of the electric signal may be inverted. That is, the output lines of the transmission circuits 21a, 21b, 22a to 22c are branched into two systems, one output line is connected to one of the coils 24a, 24b in a normal connection form, and the other output line is in a normal connection form. It may be connected to the other of the coils 24a and 24b in a form in which a current flows in the opposite direction to the above. In this case, the phase adjustment circuit 23 may be omitted.

The configuration of the superimposition circuit 24 is not limited to the configuration shown in FIG. 3B, but is another configuration as long as the two electrical signals are superposed so as to include the frequency components of the two electrical signals. You may.

Returning to FIG. 2, the superimposition circuit 24 is the least common multiple of the number of transmitting elements 11a (here, 4) included in the group GR1 and the number of transmitting elements 11a (here, 6) included in the group GR2. Only a number (12 in this case) are arranged. The electric signals output from the 12 superimposing circuits 24 are input to the 12 continuously arranged wave transmitting elements 11a, respectively. In FIG. 2, the 1st to 12th transmission elements 11a, the 13th to 24th transmission elements 11a, the 25th to 36th transmission elements 11a, the 37th to 48th transmission elements 11a, and 49 to 49 to The electric signals output from the 12 superimposing circuits 24 are input to the 60th transmitting element 11a and the 61st to 72nd transmitting elements 11a, respectively.

Here, the first set of electric signals input to the transmission element 11a of the group GR1, that is, the electrical signals output from the transmission circuits 21a and 21b whose phase is shifted by 90 °, and the transmission element of the group GR2. The second set of electric signals input to 11a, that is, the electric signals phase-shifted by 60 ° output from the transmission circuits 22a to 22c, have different frequencies depending on the first frequency table and the second frequency table. Is applied. Therefore, even if these electric signals are superimposed and input to the wave transmitting element 11a, the grating lobes are individually formed by the electric signals of each set.

Therefore, by inputting an electric signal to the 72 transmitting elements 11a as described above, the grating lobe based on the first set of electric signals phase-shifted by 90 degrees from the transmitting element 11a of the group GR1. Is formed, and a grating lobe based on a second set of electrical signals phase-shifted by 60 degrees is formed from the wave transmitting element 11a of the group GR2. Then, by changing the frequency of each set of electric signals according to the corresponding frequency table, each grating lobe can be scanned in the alignment direction of the transmitting elements 11a.

4 (a) to 8 (b) are diagrams showing the simulation results obtained by simulating the direction in which the grating lobe is generated. In FIGS. 4 (a) to 8 (b), the horizontal axis is the angle formed by the front direction of the wave transmission array 11, and the vertical axis is the intensity of the transmitted wave transmitted from the wave transmission array 11. Is. The arrangement direction of the wave transmitting elements 11a is ± 90 ° on the horizontal axis.

In this simulation, the pitch of the wave transmitting element 11a was set to 4.35 mm. The number of wave transmitting elements 11a was 72 as described above. In addition, the electric signals of the first set and the second set were changed to the above-mentioned frequencies assigned to the first frequency table and the second frequency table, respectively. Further, the phase of the electric signal applied to each transmitting element 11a was set in the same manner as in FIG.

4 (a) to 6 (c) show the case where the first set of electric signals having frequencies 95, 100, 105, 110, 120, 130 and 145 kHz are applied to the wave transmitting element 11a of the group GR1, respectively. This is a simulation result. Further, FIGS. 7 (a) to 8 (b) are simulation results when a second set of electric signals having frequencies 115, 125, 135, and 150 kHz is applied to the wave transmitting element 11a of the group GR2, respectively. ..

As shown in FIGS. 4 (a) to 6 (c), when an electric signal having frequencies 95, 100, 105, 110, 120, 130, and 145 kHz is applied to the transmitting element 11a of the group GR1, the angles D11 are different from each other. , D12, D13, D14, D15, D16, and D17. These 6 grating lobes generally cover the range of -65 ° to -35 °. Therefore, by changing the frequency of the electric signal applied to the transmitting element 11a of the group GR1 as described above, the grating lobe generated from the transmitting element 11a of the group GR1 causes a range of -65 ° to -35 °. Can be scanned.

Further, as shown in FIGS. 7 (a) to 8 (b), when an electric signal having frequencies 115, 125, 135, and 150 kHz is applied to the transmitting element 11a of the group GR2, the angles D21, D22, which are different from each other, Grating lobes are formed near D23 and D24. These four grating lobes generally cover the range of −30 ° to −23 °. Therefore, by changing the frequency of the electric signal applied to the transmitting element 11a of the group GR2 as described above, the grating lobe generated from the transmitting element 11a of the group GR2 causes a range of −30 ° to −23 °. Can be scanned.

As described above, according to the above simulation conditions, the grating lobe formed by the wave transmitting element 11a of the group GR1 can cover an angle range (-65 ° to -35 °) of approximately 30 °, and the transmission of the group GR2. The grating lobe formed by the wave element 11a can cover an angle range of approximately 7 ° (-30 ° to -23 °). Therefore, when the angle ranges of the groups GR1 and GR2 are integrated, the angle range of approximately 42 ° (−65 ° to −23 °) can be covered by the two grating lobes. That is, a viewing angle of 42 ° can be realized.

FIG. 9 is a diagram schematically showing a range covered by the transmission beam.

In FIG. 9, the transmitting beam TB1 corresponds to a grating lobe formed by the transmitting element 11a of the group GR1, and the transmitting beam TB2 corresponds to a grating lobe formed by the transmitting element 11a of the group GR2. By changing the frequency of the first set of electrical signals supplied to the transmitting element 11a of the group GR1 in the range of fa to fb, the transmitted beam TB1 is scanned in the range of the angle θ01. Further, the transmission beam TB2 is scanned in the range of the angle θ02 by changing the frequency of the second set of electric signals supplied to the transmission element 11a of the group GR2 in the range of fc to fd. Therefore, the transmission beams TB1 and TB2 can scan the range of the angle θ0 in which the angle θ01 and the angle θ02 are integrated.

In the above simulation, the frequency change ranges fa to fb in the first set of electric signals and the frequency change ranges fc to fd in the second set of electric signals are 95 to 145 kHz and 115 to 150 kHz, respectively, and the angles. θ01 and θ02 are 30 ° and 7 °, respectively, and the angle θ0 is 42 °.

In the configuration of FIG. 2 and the above simulation, the phase shift of the electric signals of the first set was set to 90 °, and the phase shift of the electric signals of the second set was set to 60 °, but the second set The phase shift of the electrical signal of may be set to 45 °. In this case, the number of transmitting elements 11a included in the group GR2 is changed according to the change in the number of combinations of electric signals accompanying the change in the phase shift.

Alternatively, the phase shift of the first set of electrical signals may be set to 45 °. Also in this case, the number of the transmitting elements 11a included in the group GR1 is changed according to the change in the number of combinations of electric signals due to the change in the phase shift.

Further, the change in the frequency of the electric signals of the first set and the second set is not limited to the above example, and can be appropriately changed according to the range of the angles θ01 and θ02.

FIG. 10 is a diagram schematically showing a configuration example of a transmission / reception system.

In this configuration example, in addition to the configuration of the wave transmitting system shown in FIG. 2, a receiving array 31 having a plurality of receiving elements 31a is arranged as a configuration of the receiving system. Similar to FIG. 2, the wave transmission system includes a wave transmission array 11. The wave transmission array 11 is arranged along the X axis. The wave receiving array 31 is arranged at a position directly above the wave transmitting array 11. In this configuration example, the arrangement direction of the receiving elements 31a and the arrangement direction of the transmitting elements 11a are perpendicular to each other.

By driving the wave transmitting element 11a in the wave transmitting array 11 by the method described with reference to FIG. 2, the transmitting beam TB0 is formed in front of the transmitting array 11 (in the positive direction of the Z axis). Here, the range in which the scanning ranges of the transmission beams TB1 and TB2 shown in FIG. 9 are integrated is shown as the scanning range of the transmission beam TB0.

By performing phase control (beamforming) on the received signal output from each receiving element 31a, a narrow receiving beam RB0 is formed in the circumferential direction centered on the X axis. As a result, the received signal in the region where the received beam RB0 and the transmitted beam TB0 intersect is extracted. By the above phase control, the reception beam RB0 is swiveled in the θ1 direction about the X axis, so that the reception signal at each swivel position is extracted. The turning position of the received beam RB0 can define the arrival direction of the reflected wave reflected by the target in the horizontal direction (θ1 direction). Further, as described with reference to FIG. 9, the arrival direction of the reflected wave in the vertical direction (θ0 direction) can be defined by the frequency of the received signal.

Therefore, among the received signals extracted by the received beam RB0, the received signals having the frequencies of the first set and the second set of electric signals are extracted, and the vertical angle corresponding to the extracted frequency (angle in the θ0 direction). ) And the horizontal angle based on beam forming (angle in the θ1 direction), by plotting the data based on the intensity of the received signal at the distance position based on the delay time of the reflected wave. The distribution of the intensity data of the received signal in the range where the received beam RB0 and the transmitted beam TB0 intersect can be obtained. Then, the reception beam RB0 is swiveled within the detection range in the horizontal direction to obtain the distribution of the intensity data at each swivel position, so that the intensity data distributed in three dimensions in all the detection ranges in the horizontal direction and the vertical direction ( Volume data) can be acquired. By imaging this intensity data (volume data), it is possible to obtain an image showing the state of the target in the detection range.

<Specific configuration>
FIG. 11 is a block diagram showing a specific configuration of the target detection device 1.

The target detection device 1 includes a wave transmission array 11 as a structure of the wave transmission system. The wave transmission array 11 has the same configuration as that of FIG. The target detection device 1 includes a signal generation unit 111 and a transmission amplifier 112 as a configuration for supplying the transmission signal S1 to each transmission element 11a of the transmission array 11. The signal generation unit 111 has a configuration similar to the circuit configuration shown in FIG. In the configuration of FIG. 11, a transmission amplifier 112 for amplifying the electric signal (transmission signal S1) output from the superimposition circuit 24 of FIG. 2 and supplying it to each transmission element 11a is further arranged. The transmission amplifier may be arranged between the transmission circuits 21a, 21b, 22a to 22c of FIG. 2 and the phase adjustment circuit 23.

The control unit 101 includes an arithmetic processing circuit such as a CPU (Central Processing Unit) and a storage medium such as a ROM (Read Only Memory), a RAM (Random Access Memory), and a hard disk. The control unit 101 may be configured by an integrated circuit such as an FPGA (Field-Programmable Gate Array).

The control unit 101 causes the transmission circuits 21a, 21b, 22a to 22c shown in FIG. 2 to output an electric signal having a frequency corresponding to the first frequency table and the second frequency table. As a result, as described with reference to FIG. 9, the transmission beams TB1 and TB2 are transmitted from the transmission array 11. As described above, the transmission beams TB1 and TB2 have angles θ01, respectively, by sequentially changing the frequencies of the first set and the second set of electric signals according to the first frequency table and the second frequency table. Scan the range of θ02. As a result, the transmission beam TB0 of FIG. 10 is configured.

The target detection device 1 includes the above-mentioned wave receiving array 31 as a structure of the wave receiving system. The wave receiving array 31 has the same configuration as that of FIG. In the wave receiving array 31, m receiving elements 31a are arranged. A reception signal is output from each receiving element 31a to channels CH1 to CHm corresponding to each receiving element 31a.

The target detection device 1 has a plurality of reception processing units 121 and a plurality of AD conversion units as a configuration for processing a reception signal output from each reception element 31a of the reception array 31 to generate a detection image. It includes 122, a received signal processing unit 123, and a video signal processing unit 124.

The plurality of reception processing units 121 are connected to channels CH1 to CHm, respectively. Each reception processing unit 121 has a process of removing an unnecessary band from the input received signal, a process of amplifying the received signal to a level suitable for AD conversion, and a band of half or more of the sampling cycle of AD conversion. Performs processing such as removing signal components. The plurality of AD conversion units 122 are associated with the plurality of reception processing units 121, respectively. Each AD conversion unit 122 converts an analog reception signal input from the corresponding reception processing unit 121 into a digital signal at a predetermined sampling cycle.

The reception signal processing unit 123 processes the reception signals of channels CH1 to CHm input from each of the plurality of AD conversion units 122, and calculates the intensity data (volume data) of the reception signals distributed three-dimensionally in the detection range. To do. The received signal processing unit 123 may be configured by a single integrated circuit (FPGA or the like) together with the control unit 101.

The video signal processing unit 124 processes the intensity data (volume data) input from the reception signal processing unit 123 to generate image data for imaging the state of the target in the detection range. The video signal processing unit 124 is composed of, for example, a CPU. The display unit 125 is composed of a monitor or the like, and displays a detected image according to the image data input from the video signal processing unit 124.

FIG. 12A is a functional block diagram showing a configuration example of the received signal processing unit 123.

The reception signal processing unit 123 includes an arithmetic processing circuit and a storage medium. The reception signal processing unit 123 executes the function of each functional block shown in FIG. 12A by the program stored in the storage medium. A part of the function of FIG. 12A may be realized by hardware instead of software.

The reception signal processing unit 123 includes a plurality of digital filters 201, a buffer 202, a plurality of bandpass filters 203, and a plurality of beam synthesizing units 204.

The plurality of digital filters 201 are provided corresponding to the plurality of AD conversion units 122 of FIG. The digital filter 201 is a filter steeper than the filter function of the reception processing unit 121 of FIG. 11, and removes signals in an unnecessary band in the reception signal.

The buffer 202 temporarily holds the received signals of channels CH1 to CHm output from the plurality of digital filters 201, respectively. The buffer 202 is a received signal while the frequencies of the electric signals output from the transmission circuits 21a, 21b, 22a to 22c are changed to all frequencies assigned to the first frequency table and the second frequency table (hereinafter, "" "Received signal for one scan") is retained for multiple scans in chronological order. The buffer 202 sequentially supplies the received signals for one scan to the plurality of bandpass filters 203, respectively. When the received signal for one scan is supplied to the plurality of bandpass filters 203, the buffer 202 erases the received signal for the one scan.

The plurality of bandpass filters 203 extract frequency components (frequency reception signals) of frequencies F1 to Fn from the reception signals for one scan of the input channels CH1 to CHm. The frequencies F1 to Fn correspond to the frequencies assigned to the first frequency table and the second frequency table, respectively. The bandpass filter 203 is arranged by the total number of frequencies assigned to the first frequency table and the second frequency table. Each bandpass filter 203 extracts the received signal of each frequency assigned to the first frequency table and the second frequency table. The bandpass filter 203 extracts a frequency component (frequency reception signal) of the frequency Fk set by itself from the reception signals for one scan of channels CH1 to CHm and supplies the frequency component (frequency reception signal) to the beam synthesis unit 204.

The plurality of beam synthesizing units 204 are provided in association with each of the plurality of bandpass filters 203. The beam combining unit 204 forms the received beam RB0 by beamforming based on phase control, and separates the frequency received signal in the θ1 direction of FIG. 10 with a predetermined resolution. As a result, the frequency reception signal in the region where the reception beam RB0 and the transmission beam TB1 or the transmission beam TB2 of FIG. 9 defined by the bandpass filter 203 intersect is acquired. That is, from the uppermost beam synthesizing unit 204, the transmission beam (either the transmission beam TB1 or TB2) in the angle θ0 direction (see FIG. 9) corresponding to the frequency F1 and the direction parallel to the horizontal plane (θ1 in FIG. 10). A frequency reception signal in an intersection region where the reception beam RB0 in each direction intersects in the direction) is obtained.

The intensity of the obtained frequency received signal changes on the time axis according to the intensity of the reflected wave from the intersecting region. This time axis corresponds to the distance from the receiving array 31 in the intersection region. Therefore, by mapping each intensity on the time axis to the corresponding distance position from the receiving array 31 in the intersection region, the distribution of the intensity data on the intersection region can be obtained. In this way, by integrating the distribution of the intensity data for each direction output from each beam combining unit 204, the volume data in which the intensity data is three-dimensionally distributed in the detection range is acquired.

FIG. 12B is a functional block diagram showing another configuration example of the received signal processing unit 123.

In this configuration example, the bandpass filter 203 in the configuration example of FIG. 12A is replaced with the FFT (Fast Fourier Transform) 211 and the frequency extraction unit 212. FFT211 calculates the frequency spectrum from the received signals for one scan of channels CH1 to CHm. The frequency extraction unit 212 extracts frequency components (frequency reception signals) of frequencies F1 to Fn from the frequency spectrum of each channel calculated by FFT211 and supplies them to the beam synthesis unit 204. The processing of the beam synthesizing unit 204 is the same as in the case of FIG. 12A.

With this configuration as well, as in the configuration of FIG. 12A, the intensity data is distributed three-dimensionally in the detection range by integrating the distribution of the intensity data for each direction output from each beam synthesizer 204. Data is retrieved. In the configuration example of FIG. 12B, the frequency for extracting the frequency reception signal can be set more finely than in the configuration example of FIG. 12A. Therefore, when the number of a plurality of frequencies assigned to the first frequency table and the second frequency table is large, or when these frequencies are close to each other, it is advantageous to use the configuration of FIG. 12B.

13 (a) and 13 (b) are flowcharts showing a wave transmission process performed by the control unit 101 of FIG. This process is continuously executed during the detection operation and is terminated when the detection operation ends. Further, the processes of FIGS. 13A and 13B are executed in synchronization with each other.

FIG. 13A is a flowchart showing a wave transmission process for the wave transmission element 11a of the group GR1.

The control unit 101 sets the electric signal output from the transmission circuits 21a and 21b to the first frequency assigned to the first frequency table (S111), and outputs the electric signal to the transmission circuits 21a and 21b for a predetermined period. (S112). As a result, the first set of electric signals is input to the transmission element 11a of the group GR1 via the superimposition circuit 24 (S113), and the grating lobe (transmission) based on the first set of electric signals is transmitted from the transmission array 11. The beam TB1) is transmitted.

After that, the control unit 101 waits for a predetermined period of the electric signal to elapse (S114: NO). When the predetermined period elapses and the next transmission timing arrives (S114: YES), the control unit 101 returns the process to step S111 and displays the electric signals output from the transmission circuits 21a and 21b in the first frequency table. Set to the second frequency assigned to, and perform the same process. As a result, the wave transmission direction of the grating lobe (transmission beam TB1) changes in the direction of the angle θ01 in FIG. The control unit 101 repeats the same process until the last frequency assigned to the first frequency table is applied to the transmission circuits 21a and 21b (S115: NO). As a result, the transmission direction of the grating lobe (transmission beam TB1) is switched within the range of the angle θ01 in FIG. 9, and the range of the angle θ01 is scanned by the grating lobe (transmission beam TB1).

In this way, when all the frequencies assigned to the first frequency table are applied to the transmission circuits 21a and 21b to transmit the transmission beam TB1 for one scan (S115: YES), the control unit 101 performs processing. finish. In this way, after the final transmission for one scan is performed, the control unit 101 interrupts the transmission until the reception period for the transmission ends. Then, when the reception period ends, the control unit 101 executes the process of FIG. 13A again to transmit waves for the next scan. In this way, the control unit 101 transmits the grating lobe (transmission beam TB1) to the transmission array 11 while cyclically switching the frequencies applied to the transmission circuits 21a and 21b with respect to the frequencies assigned to the first frequency table. Let me. As a result, the range of the angle θ01 in FIG. 9 is repeatedly scanned by the transmission beam TB1.

FIG. 13B is a flowchart showing a wave transmission process for the wave transmission element 11a of the group GR2.

The control unit 101 sets the electric signal output from the transmission circuits 22a to 22c to the first frequency assigned to the second frequency table (S121), and outputs the electric signal to the transmission circuits 22a to 22c for a predetermined period. (S122). As a result, the second set of electric signals is input to the transmission element 11a of the group GR2 via the superimposition circuit 24 (S123), and the grating lobe (transmission) based on the second set of electric signals is transmitted from the transmission array 11. The beam TB2) is transmitted.

After that, the control unit 101 performs steps S121 to S124 until the last frequency assigned to the second frequency table is applied to the transmission circuits 22a to 22c (S125: NO), as in the case of FIG. 13A. Repeat the process. Further, when the reception period for the last wave transmission for one scan ends, the control unit 101 executes the process of FIG. 13A again, and repeats the same wave transmission process. As a result, the grating lobe (transmission beam TB2) is transmitted from the transmission array 11 while the frequencies applied to the transmission circuits 22a to 22c are cyclically switched with respect to the frequencies assigned to the second frequency table. In this way, the range of the angle θ02 in FIG. 9 is scanned by the grating lobe (transmission beam TB2).

In the present embodiment, the number of frequencies assigned to the second frequency table is smaller than the number of frequencies assigned to the first frequency table. Therefore, when the switching timings of steps S114 and S124 are the same, all the frequencies are assigned. The period in which the frequency is applied to each transmission circuit is shorter in the process of FIG. 13 (b) than in the process of FIG. 13 (a). Therefore, the control unit 101 takes steps S114 so that the period during which all frequencies are applied to each transmission circuit is the same between the process of FIG. 13 (a) and the process of FIG. 13 (b). Adjust the switching timing of S124.

Alternatively, the control unit 101 interrupts the process of FIG. 13 (b) after completing the process of FIG. 13 (b) for one scan, and then interrupts the process of FIG. 13 (b) until the process of FIG. 13 (a) is completed for one scan. After the process of (a) is completed for one scan, the process of the next scan of FIG. 13 (b) is started at the timing when the last reception period is completed. As a result, it becomes possible to acquire the received signal for one scan for each process at regular intervals.

FIG. 14 is a flowchart showing a process of processing a received signal and displaying a detected image. This process is continuously executed during the detection operation and is terminated when the detection operation ends.

The received signal for one scan is supplied from the buffer 202 to the plurality of bandpass filters 203, respectively (S201). Each bandpass filter 203 extracts a frequency component (frequency reception signal) of the frequency set by itself from the input reception signal of each channel and supplies it to the corresponding beam synthesis unit 204 (S202). The beam synthesizing unit 204 extracts signal components in each direction in the horizontal direction (θ1 direction) from the input frequency components (frequency reception signals) by beamforming (S203). As a result, it is possible to obtain a distribution of intensity data in which the intensity data of the received signal is mapped to the range where the wave transmission direction defined by each frequency and each direction by beamforming intersect. The reception signal processing unit 123 integrates the intensity data from all the beam synthesizing units 204 to form volume data in which the intensity data is three-dimensionally distributed in the detection range (S204). The reception signal processing unit 123 supplies the volume data to the video signal processing unit 124.

The video signal processing unit 124 processes the volume data to generate image data for displaying the detection status of the target in the detection range, and supplies the generated image data to the display unit 125 (S205). The display unit 125 displays an image based on the input image data (S206). As a result, the detection status of the target for one scan in the detection range is displayed. In this way, the processing for one scan is completed. After that, the process of FIG. 14 is repeatedly executed, and the detected image for the subsequent scan is displayed on the display unit 125.

FIG. 15 is a diagram schematically showing a configuration when the above-mentioned target detection device 1 is used as a sonar for detecting a target in water.

A transmitter / receiver 300 is installed on the bottom of the ship 2. The transmitter / receiver 300 includes a transmitter array 11 and a receiver array 31. The wave transmission array 11 transmits a transmitted wave into the water by the above-mentioned process. Here, sound waves (for example, ultrasonic waves) are transmitted as transmitted waves. As a result, the transmission beams TB1 and TB2 are scanned in a range of an angle θ0 parallel to the vertical plane.

Of the configurations shown in FIG. 11, the configurations other than the transmission array 11, the reception array 31 and the display unit 125 are mounted on the control device installed in the wheelhouse 2a of the ship 2. The display unit 125 is installed in the wheelhouse 2a separately from the control device. The display unit 125 may be integrated with the control device.

According to this configuration, a detection image showing the status of the water bottom 3 and the school of fish 4 is displayed on the display unit 125. As a result, the user can grasp the underwater situation. It should be noted that four transmitters / receivers 300, which are directed to the front, the rear, the left, and the right, may be installed on the bottom of the ship. In this case, the transmission system and the configuration of the reception system shown in FIG. 11 are prepared for each of the transmitter / receiver 300. As a result, the detection image of the entire circumference of the ship can be displayed on the display unit 125.

Further, when the above-mentioned target detection device 1 is used as a radar for detecting a target in the air, for example, a transmitter / receiver 400 is installed above the wheelhouse 2a. The transmitter / receiver 400 includes a transmitter array 11 and a receiver array 31. The wave transmission array 11 transmits a transmitted wave into the air by the above processing. Here, radio waves are transmitted as transmitted waves. The configuration of the circuit unit is installed in the wheelhouse 2a as in the case of sonar.

According to this configuration, a detection image showing the situation of an obstacle, a flock of birds, or the like is displayed on the display unit 125. As a result, the user can grasp the situation in the air. The transmitter / receiver 400 may be installed on each of the front, rear, left, and right sides of the wheelhouse 2a. In this case, the transmission system and the configuration of the reception system shown in FIG. 11 are prepared for each transmitter / receiver 400. As a result, the detection image of the space around the entire ship can be displayed on the display unit 125.

<Effect of embodiment>
According to the embodiment, the following effects can be achieved.

A grating lobe transmitted from the transmitting element 11a grouped according to the first group configuration (group GR1) and a grating lobe transmitted from the transmitting element 11a grouped according to the second group configuration (group GR2). The wave transmission direction can be different from that of. Therefore, one transmission array 11 can transmit a plurality of transmission beams (grating lobes) having different transmission directions. Therefore, the target can be detected smoothly with a simple configuration.

Further, since the common wave transmitting element 11a is used for the first group configuration and the second group configuration, it is not necessary to prepare the transmitting element 11a for each of the first group configuration and the second group configuration. Therefore, the configuration of the wave transmission array 11 can be simplified and the cost can be reduced.

Further, since the interval between the wave transmitting elements 11a is constant, the grating lobe can be smoothly generated in a predetermined wave transmitting direction by adjusting the phases of the electric signals of the first set and the second set. ..

Further, as shown in FIG. 2, a superimposition circuit 24 that superimposes each electric signal of the first set and each electric signal of the second set and inputs the superposed electric signal to the corresponding transmitting element 11a. Since they are arranged, as shown in FIG. 9, the grating lobe (transmission beam TB1) based on the first set of electrical signals and the grating lobe (transmission beam TB2) based on the second set of electrical signals are arranged. It is possible to send waves at the same time. Therefore, it is possible to quickly detect a target in the detection area.

Further, the frequencies of the first set of electric signals assigned to the first frequency table and the frequencies of the second set of electric signals assigned to the second frequency table are different from each other. Therefore, in the received signal processing unit 123 shown in FIG. 11, the received signal based on the grating lobe of the first set of electric signals and the received signal based on the grating lobe of the second set of electric signals are divided by frequency. , Can be extracted. Therefore, even if these two grating lobes are simultaneously transmitted by the superimposition of the electric signal by the superimposition circuit 24, the reception signal based on each grating lobe can be appropriately extracted by the reception signal processing unit 123, and each grating globe can be appropriately extracted. Targets existing in the direction can be detected smoothly.

As shown in FIGS. 13 (a) and 13 (b), the signal generation unit 111 changes the frequency of the first set of electric signals according to the first frequency table, and changes the frequency of the second set of electric signals to the second. 2 Change according to the frequency table. By changing the frequency in this way, as shown in the above simulation result, it is possible to change the transmission direction of the grating lobe based on the first set of electric signals and the second set of electric signals, respectively. Thereby, each of these grating lobes can scan a predetermined angle range, and the detection range of the target can be expanded.

As described with reference to FIGS. 12A and 12B, the reception signal processing unit 123 extracts the reception signal based on the reflected wave of the grating lobe based on the frequency component of the reception signal. As a result, the received signal based on each grating lobe transmitted from the transmission array 11 can be appropriately acquired. Therefore, the target can be properly detected based on the received signal.

As shown in FIG. 10, the receiving array 31 includes a plurality of receiving elements 31a, and unlike the transmitting array 11, the receiving array 31 is generated based on the received signal generated from each receiving element 31a. The received beam intersects the transmitted beam generated by the wave array 11. With this configuration, the distribution of intensity data based on the intensity of the reflected wave can be calculated in the range where the received beam RB0 and the transmitted beam TB0 (grating lobe) intersect. Therefore, by changing the directivity direction of the received beam RB0 within the detection range by beamforming, it is possible to construct the intensity data of the reflected wave distributed three-dimensionally in the detection range.

<Change example 1>
In the above embodiment, as shown in FIG. 2, two systems of electric signals are superposed by the superimposing circuit 24 and input to the corresponding transmitting element 11a. However, as shown in FIG. 16, the transmitting element 11a is input. The electric signal input to may be switched to one of the two electric signals in a time-division manner. In this configuration, while one frequency is applied to the transmission circuits 21a, 21b, 22a-22c, the switching circuit 25 is switched to provide a first set of electrical signals and a second set of electricity at that frequency. The signal is supplied to the wave transmitting element 11a in a time division manner. According to this configuration, the transmission beams TB1 and TB2 shown in FIG. 9 are not simultaneously transmitted, but are alternately transmitted according to the switching of the switching circuit 25.

Also in this configuration, the angles θ01, by the transmission beams TB1 and TB2, by switching the frequencies applied to the transmission circuits 21a, 21b, 22a to 22c according to the first frequency table and the second frequency table, as in the above embodiment. The range of θ02 can be scanned. Therefore, it is not necessary to provide a plurality of wave transmission arrays 11, and the target can be detected by a simple configuration.

However, in this configuration, the transmission beams TB1 and TB2 are not simultaneously transmitted, but are alternately transmitted according to the switching of the switching circuit 25. Therefore, the transmission beams TB1 and TB2 scan the range of angles θ01 and θ02. The period will be longer. Therefore, in order to perform scanning more quickly, it is preferable to have a configuration in which two systems of electric signals are superposed by the superimposing circuit 24 and supplied to the transmitting element 11a as in the above embodiment.

In the configuration of FIG. 16, the switching circuit 25 may be configured by, for example, a multiplexer or a switching circuit using a transistor. However, the configuration of the switching circuit 25 is not limited to this. For example, an electromagnetically driven mechanical switch may be used as the switching circuit 25.

In the configuration of the first modification, the first set of electric signals and the second set of electric signals are input in a time division manner to the transmission element 11a of the group GR1 and the transmission element 11a of the group GR2. , The transmission beams TB1 and TB2 (grating lobes) of FIG. 9 are transmitted in a time-division manner. Therefore, the received signal processing unit 123 of FIG. 11 does not necessarily have a configuration for extracting the received signal based on the first set of electric signals and the received signal based on the second set of electric signals by frequency. In some cases, the transmission directions of the transmission beams TB1 and TB2 may be specified by the transmission timing of the transmission beams TB1 and TB2.

In this case, for example, the control unit 101 outputs the frequency of the transmitted beam transmitted at each transmission timing to the reception signal processing unit 123, and the reception signal processing unit 123 outputs the transmission beam based on the input frequency. The wave transmission directions of TB1 and TB2 may be specified. Alternatively, the control unit 101 transmits other information capable of specifying the transmission directions of the transmitted transmission beams TB1 and TB2 to the reception signal processing unit 123 at each transmission timing, and the reception signal processing unit 123 sends the reception signal processing unit 123. , The transmission direction of the transmitted transmission beams TB1 and TB2 may be specified based on this information.

<Change example 2>
In the above embodiment, electric signals having different phases are input to the plurality of transmitting elements 11a constituting the group GR1 and the group GR2, respectively, but in the second modification, the group GR1 and the group GR2 are respectively configured. Electric signals having the same phase are input to a predetermined number of wave transmitting elements 11a among the plurality of transmitting elements 11a.

FIG. 17 is a diagram showing a configuration of a wave transmission system according to the second modification.

As shown in FIG. 17, in the first group configuration, the group GR1 is composed of the six transmitting elements 11a, and in the second group configuration, the group GR2 is composed of the eight transmitting elements 11a. Of the six transmitter elements 11a constituting the group GR1, the first set of electric signals having a phase of 0 ° is input to the three consecutive transmitter elements 11a, and the other three consecutive transmitter elements 11a A first set of electrical signals with a phase of 180 ° is input. Further, of the eight transmitting elements 11a constituting the group GR2, a second set of electric signals having a phase of 0 ° is input to the four continuous transmitting elements 11a, and the other four continuous transmitting elements A second set of electrical signals having a phase of 180 ° is input to 11a. The first set and the second set of electric signals are input to the 25th and subsequent transmission elements 11a so that the same phase pattern as that of the 1st to 24th transmission elements 11a is repeated.

In the configuration of the second modification, two types of electric signals having different phases are input to the six transmitting elements 11a included in the group GR1. That is, the number (6) of the wave transmitting elements 11a included in the group GR1 is a multiple (3 times) of the number (2) of the types of electric signals of the first set. Further, two types of electric signals having different phases are input to the eight transmitting elements 11a included in the group GR2. That is, the number (8) of the wave transmitting elements 11a included in the group GR2 is a multiple (4 times) of the number (2) of the types of electric signals of the second set. Also in the above embodiment, the number (4, 6) of the wave transmitting elements 11a included in the group GR1 and the group GR2, respectively, is the number of types of electric signals of the first set and the second set (4). It is a multiple (1 times) of 6).

The first set of electrical signals is generated by a transmission circuit 26 and a phase adjustment circuit 28 connected to the transmission circuit 26. The second set of electrical signals is generated by the transmission circuit 27 and the phase adjustment circuit 28 connected to the transmission circuit 27. The phase adjustment circuit 28 has the same configuration as the phase adjustment circuit 23 of the above embodiment. The superimposition circuit 29 superimposes and outputs the two input electric signals. The superimposition circuit 29 has the same configuration as the superimposition circuit 24 of the above embodiment.

The transmission circuits 26 and 27 each output a sinusoidal electric signal having a phase of 0 °. The transmission circuit 26 switches the frequency of the output electric signal based on the frequency assigned to the first frequency table. The first frequency table is assigned, for example, frequencies of 130, 140, 150, 160, 170 kHz. The transmission circuit 27 switches the frequency of the output electric signal based on the frequency assigned to the second frequency table. The second frequency table is assigned frequencies of, for example, 135, 145, 155, 165 kHz.

In the configuration of FIG. 17, among the six transmission elements 11a of the group GR1, since the electric signals having the same phase are input to the three consecutive transmission elements 11a, the three consecutive transmission elements 11a are one transmission. Functions as a wave region. Therefore, for the transmission element 11a of the group GR1, the phase of the electric signal changes at the pitch between the transmission regions composed of the three consecutive transmission elements 11a. For example, when the pitch between the wave transmitting elements 11a is 2.5 mm, the pitch at which the phase of the electric signal changes is 7.5 mm.

Further, since the electric signals having the same phase are input to the four continuous transmission elements 11a among the eight transmission elements 11a of the group GR2, the four consecutive transmission elements 11a function as one transmission region. To do. Therefore, with respect to the transmission element 11a of the group GR2, the phase of the electric signal changes at the pitch between the transmission regions composed of the four consecutive transmission elements 11a. For example, when the pitch between the wave transmitting elements 11a is 2.5 mm, the pitch at which the phase of the electric signal changes is 10 mm.

As described above, in the second modification, the first set of electric signals is input to the transmitting element 11a of the group GR1 and the second set of electric signals is input to the transmitting element 11a of the group GR2. Therefore, the pitch at which the phase of the electric signal is switched is different. As a result, the transmission direction of the grating lobe generated by the transmission element 11a of the group GR1 and the transmission direction of the grating lobe generated by the transmission element 11a of the group GR2 are different from each other. Then, by changing the frequencies of the first set of electric signals and the second set of electric signals according to the first frequency table and the second frequency table, respectively, the wave transmission direction of each grating lobe is changed as in the above embodiment. Can be changed. As a result, the two grating lobes (transmitted beams) can be scanned in a predetermined detection range.

18 (a) to 21 (b) are diagrams showing the simulation results obtained by simulating the wave transmission direction in which the grating lobe is generated in the configuration of the second modification.

In this simulation, the pitch of the wave transmitting element 11a was set to 2.5 mm. The number of wave transmitting elements 11a was 96. Further, the first set of electric signals and the second set of electric signals were changed to the above frequencies assigned to the first frequency table and the second frequency table, respectively. Further, the phase of the electric signal applied to each transmitting element 11a was set in the same manner as in FIG.

18 (a) to 19 (c) are simulation results when a first set of electric signals having frequencies of 130, 140, 150, 160, and 170 kHz are applied to the transmission element 11a of the group GR1, respectively. .. 20 (a) to 21 (b) are simulation results when a second set of electric signals having frequencies 135, 145, 155, and 165 kHz is applied to the wave transmitting element 11a of the group GR2, respectively. ..

As shown in FIGS. 18 (a) to 19 (c), when an electric signal having a frequency of 130, 140, 150, 160, 170 kHz is applied to the transmitting element 11a of the group GR1, the angles D11, D12, D13 are different from each other. , D14, D15 and grating lobes are formed. These five grating lobes generally cover the range of −50 ° to −36 °. Therefore, by changing the frequency of the electric signal applied to the transmitting element 11a of the group GR1 as described above, the grating lobe generated from the transmitting element 11a of the group GR1 causes a range of −50 ° to −36 °. Can be scanned.

Further, as shown in FIGS. 20A to 21B, when an electric signal having a frequency of 135, 145, 155, or 165 kHz is applied to the transmitting element 11a of the group GR2, the angles D21, D22, which are different from each other, Grating lobes are formed near D23 and D24. These four grating lobes generally cover the range of −34 ° to −27 °. Therefore, by changing the frequency of the electric signal applied to the transmitting element 11a of the group GR2 as described above, the grating lobe generated from the transmitting element 11a of the group GR2 causes a range of −34 ° to −27 °. Can be scanned.

As described above, according to the above simulation conditions, the grating lobe formed by the wave transmitting element 11a of the group GR1 can cover an angle range of approximately 14 ° (-50 ° to −36 °), and the transmission of the group GR2. The grating lobe formed by the wave element 11a can cover an angle range of approximately 7 ° (−34 ° to −27 °). When the angle ranges of the groups GR1 and GR2 are integrated, the angle range of approximately 23 ° (-50 ° to −27 °) can be covered by the two grating lobes. That is, a viewing angle of 23 ° can be realized.

Therefore, even with the configuration of the second modification, the angle range of approximately 23 ° can be scanned by the one grating lobe generated by the transmitting element 11a of the group GR1 and the one grating lobe generated by the transmitting element 11a of the group GR2.

In the configuration of the second modification, as shown in the above simulation results, two grating lobes are generated by the transmitting element 11a and the group GR2 of the group GR1 respectively. In this case, for the detection of the target, for example, only one of the two grating lobes (for example, in the simulation of FIGS. 18A to 21B, the grating lobe on the minus side) may be used. For example, the angular range of the reception beam RB0 may be set so that the other grating lobe is out of the range of the reception beam RB0. As a result, the detection image in the predetermined detection range is displayed on the display unit 125 by performing the processes of FIGS. 13 (a) to 14 using the same circuit configuration as in FIGS. 11 to 12 (b). Can be done.

<Other changes>
In the above embodiment, as shown in FIGS. 12A and 12B, after the frequency components of each frequency are extracted from the received signal, they are separated into signals in each direction by the beam forming process, but first. The received signal may be separated into signals in each direction by the beam forming process, and the frequency components of each frequency may be extracted from the separated signals in each direction. That is, the bandpass filter 203 and the beam synthesis unit 204 in FIG. 12A may be replaced with each other, and the FFT 211 and the frequency extraction unit 212 and the beam synthesis unit 204 in FIG. 12B are replaced with each other. You may.

Further, in the above embodiment, as shown in FIG. 10, a plurality of receiving elements 31a are provided, but the reflected wave may be received only by one receiving element 31a. However, in this case, since beamforming with respect to the received beam cannot be performed, the direction of the received beam (direction of θ1 in FIG. 10) is fixed. However, by extracting the frequency component of the received signal from the received beam in that direction, the intensity data in each direction in the vertical direction can be acquired. Therefore, by mapping the intensity data in each direction in the vertical direction, a two-dimensional detection image can be displayed.

Further, the number of the wave transmitting elements 11a is not limited to the number shown in the above embodiment, and may be any other number as long as a plurality of types of group configurations can be realized. Further, three or more types of group configurations may be set for the plurality of transmitting elements 11a included in the transmitting array 11, and the number of transmitting elements 11a included in each group is also the above-described embodiment and modified examples. It is not limited to the numbers listed in. In either case, a number of grating lobes corresponding to the number of group configurations are formed as transmitted waves.

Further, the grating lobes formed by the wave transmitting elements 11a of each group do not necessarily have to be clearly separated, and some of them may overlap.

Further, in the above embodiment, the transmitting array and the receiving array are arranged vertically to each other, but the transmitting array and the receiving array may be arranged at an angle slightly deviated from the vertical.

Further, FIG. 14 shows a configuration in which the target detection device 1 (sonar, radar) is arranged on the ship 2, but the target detection device 1 (sonar, radar) moves other than the ship 2. The target detection device 1 (sonar, radar) may be installed on a structure other than a moving body such as a floating target.

In addition, various modifications of the embodiment of the present invention can be made as appropriate within the scope of the claims.

1 Target detection device 11 Wave transmission array 11a Wave transmission element 24 Superimposition circuit 25 Switching circuit 31 Wave reception array 31a Wave reception element 101 Control unit 111 Signal generation unit 123 Received signal processing unit GR1 1st group GR2 2nd group

Claims (19)

In the target detection device
A transmission array with multiple transmission elements that convert electrical signals into transmission waves,
A signal generation unit that generates a plurality of sets of electric signals including a first set of electric signals and a second set of electric signals different from the first set with different phase settings for each set. ,
With
The signal generator
The plurality of wave transmitting elements are grouped according to a plurality of group configurations including a first group configuration and a second group configuration.
In the first group configuration, the plurality of transmitter elements are grouped into a plurality of groups each having n of the transmitter elements.
In the second group configuration, the plurality of transmitting elements are grouped into a plurality of groups each having m of the transmitting elements different from the n.
An electric signal of the first set is input to each group of the first group configuration.
A target detection device that inputs the second set of electric signals to each group having the second group configuration. In the target detection device according to claim 1,
The signal generation unit generates the first set of electric signals having the same phase shift between the electric signals, and generates the second set of electric signals having the same phase shift between the electric signals. Detection device. In the target detection device according to claim 1 or 2.
The target detection device, wherein the plurality of transmitting elements used in the first group configuration and the plurality of transmitting elements used in the second group configuration are the same. In the target detection device according to any one of claims 1 to 3,
A target detection device in which the plurality of wave transmitting elements are arranged at equal intervals. In the target detection device according to any one of claims 1 to 4,
The target detection device, wherein n is a multiple of the number of electric signals of the first set. In the target detection device according to any one of claims 1 to 5,
The target detection device, wherein m is a multiple of the number of electric signals of the second set. In the target detection device according to any one of claims 1 to 6,
A target detection device further comprising a superimposing circuit that superimposes the first set of electric signals and the second set of electric signals and inputs the superposed electric signals to the plurality of transmitting elements. In the target detection device according to any one of claims 1 to 6,
The first set of electric signals and the second set of electric signals are input, first, the first set of electric signals is output to the wave transmission array, and then the second set of electric signals is output. A target detection device further including a switching circuit for outputting an electric signal to the wave transmission array. In the target detection device according to any one of claims 1 to 8.
A target detection device in which the frequencies of the first set of electric signals and the frequencies of the second set of electric signals are different. In the target detection device according to any one of claims 1 to 9,
The signal generation unit is a target detection device that changes the frequencies of the first set of electric signals and the second set of electric signals. In the target detection device according to any one of claims 1 to 10.
A target detection device further comprising a receiving array including at least one receiving element that receives a reflected wave generated by reflection of the transmitted wave in a target and converts the reflected wave into a received signal. In the target detection device according to claim 11,
A reception signal processing unit that processes the reception signal is further provided.
The reception signal processing unit is a target detection device that extracts an isofrequency reception signal based on the reflected wave corresponding to the frequency based on the frequency component of the reception signal. In the target detection device according to claim 12,
The received signal processing unit
A target detection device that acquires the same frequency reception signal corresponding to each frequency by extracting a plurality of frequency components extracted at different frequencies from the reception signal. In the target detection device according to claim 12,
The received signal processing unit
The frequency spectrum of the received signal is calculated and
A target detection device that acquires the same frequency reception signal corresponding to each frequency based on the frequency spectrum. In the target detection device according to any one of claims 12 to 14,
The receiving array includes a plurality of receiving elements and includes a plurality of receiving elements.
The received signal processing unit executes beamforming based on the received signal generated from each of the receiving elements, and calculates the direction of arrival of the reflected wave from the target based on the beam forming, target detection. apparatus. In the target detection device according to any one of claims 11 to 15.
The receiving array includes a plurality of receiving elements and includes a plurality of receiving elements.
The wave receiving array is different from the wave transmitting array.
A target detection device in which a received beam generated based on a received signal generated from each of the receiving elements intersects a transmitting beam generated by the transmitting array. In the target detection device according to any one of claims 1 to 16.
The target detection device is a target detection device that is a sonar that detects a target in water. In the target detection device according to any one of claims 1 to 16.
The target detection device is a target detection device that is a radar that detects a target in the air. In a target detection method for detecting a target by transmitting a transmitted wave from a transmission array having a plurality of transmitting elements that convert an electric signal into a transmitted wave.
Due to the transmission of the transmitted wave, the wave array is
The plurality of wave transmitting elements are grouped according to a plurality of group configurations including a first group configuration and a second group configuration.
In the first group configuration, the plurality of transmitter elements are grouped into a plurality of groups each having n of the transmitter elements.
In the second group configuration, the plurality of transmitting elements are grouped into a plurality of groups each having m of the transmitting elements different from the n.
The target detection method is
A plurality of sets of electric signals including a first set of electric signals and a second set of electric signals different from the first set are generated by different phase settings for each set.
An electric signal of the first set is input to each group of the first group configuration.
A target detection method in which the second set of electric signals is input to each group having the second group configuration.

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